Mayor of London Boris Johnson leaves the stage on a traditional Malaysian tricycle after giving a speech

Boris Johnson today said it is part of human nature to be xenophobic and that those who were afraid of foreigners were “not bad people”.

But the London Mayor said it is up to politicians to highlight benefits immigrants bring and call for a “welcoming policy” for those wanting to work in the UK.

His words in an exclusive interview with the Standard come after a week-long tour which has seen him hold talks with world leaders in some of the most dynamic world economies.

As the Chancellor announced money to help develop Crossrail 2, Mr Johnson said the ambitious rail scheme could attract investment from the wealthy in Malaysia, Singapore and Indonesia.

He also said he would hammer down the £20 billion cost, while suggesting that a council tax increase to pay for it was off the table.

The Mayor finished his trip by delivering a keynote speech to an audience including the Prime Minister of Malaysia in which he drilled home a message that the UK needs to stay open.

It has been a key theme at a time when the immigration debate has dominated and soon after the Prime Minister announced a major crackdown on benefits tourism.

Last week in Singapore the Mayor said there was a “certain amount of xenophobia” in the UK debate.

Speaking in Kuala Lumpur he expanded: “All human beings are prey to that feeling.

“It’s part of human nature. It doesn’t mean people are bad people, ok?

“What we’ve got to do is point out that there are benefits of immigration and that there are benefits of having talented people, and having a welcoming policy to people that will work hard.”

Yesterday’s event was the second time Mr Johnson saw the Prime Minister of Malaysia. During his visit he also held talks with the Prime Minister of Singapore and became the highest ranking British politician to hold talks with the President of Indonesia.

He said: “These things are always very hard to know that they’re going to work in advance. But I think we’ve over achieved here, there’s no question at all that this has been a great, great trip to South East Asia. We’ve helped to broker all sorts of deals with tech companies.”

Mr Johnson went on: “[There is] yet more interest in creating housing in London and that is always good news. We are not awash as you know with public funds in Britain to spend on this.

“We are not awash unfortunately with billionaires of our own who can spend on this. It’s good that you’ve got international investors who are coming into our market and helping us support the single most vital thing we’ve got to deliver for Londoners.”

But his trip has not been without controversy. On Monday he charmed an audience of investors, some of whom are pouring money into the Battersea Power Station development, while critics in London claimed ordinary people were being priced out of the market.

Mr Johnson has been at pains to say that without foreign billionaires there may not be enough money to meet London’s infrastructure needs.

At the start of his trip it emerged that the much needed north to south rail scheme, Crossrail 2, would cost £20 billion for the Metro route and up to £27 billion for a broader regional route.

Asked if investors from his trip might be interested in helping London pay he said: “Very possibly.”

Under current proposals the Treasury will cover half of the Crossrail 2 cost, Mr Johnson added: “We think we [in London] can provide more than half of the £20 billion bill.

“We think there’s a lot of risk, a lot of contingency in that, we think that’s a bit high, we think we can get that bill well down. But we think that [with] the uplift that you’ll see in…property values as a result from Crossrail 2 we’ll be able to fund that project.”

The same funding report said one way to help pay would be to maintain the Olympic surcharge added to Londoners’ council tax bills.

When re-elected Mr Johnson promised to cut what people pay the Greater London Authority by 10 per cent.

But documents suggest he may only hit the target because the Olympic surcharge is expiring, making it politically tough to maintain it for anything else.

Asked if he favoured funding Crossrail through council tax he said there was a long way to go before decisions were made, adding: “We’re confident we can keep cutting council tax and that’s what we’ll do.”

Wherever he goes in the world there will always be a question that follows. The one of his future ambitions.

He was asked several times on tour what he planned, but is yet to run out of answers failing to rule out a bid for the top job.

He said: “After my term of office as Mayor has expired, I fully expect David Cameron still to be in place and David Cameron to be in place for a long time to come.

“The babe is probably not yet born who will replace David Cameron. That’s a slight exaggeration, but there’s oodles of people who may one day step into those shoes. But it’s certainly not going to happen for a while.”